347 or 351???

[Graham]

Hi Guys,

If I go for a stroker engine, what are the pitfalls of each of these, and which will suit my needs better. The plan is for the car to be road use (maybe a very occasional track day), but mostly road use of around 5-6000 miles per year. I'm looking to hit around 400 HP if poss, and am unsure as to whether to go EFI or Carb as yet, although EFI does look bloody expensive....

It's brain picking time!

Thanks guys,

Graham.

 

[Randy V]

Hi Guys,

If I go for a stroker engine, what are the pitfalls of each of these, and which will suit my needs better. The plan is for the car to be road use (maybe a very occasional track day), but mostly road use of around 5-6000 miles per year. I'm looking to hit around 400 HP if poss, and am unsure as to whether to go EFI or Carb as yet, although EFI does look bloody expensive....

It's brain picking time!

Thanks guys,

Graham.

Hi Graham,

If you already have the headers for your car and they're for the 289-302, you're not going to be able to use them for the 351w.
For my money - I will never build a 347 from a stock block as I've seen/heard of too many block failures when being trashed at the track. Even though your purposes are mostly road use, I would still be very leery of the block's strength.
Now if you based it on the new Ford Boss 302 block - go for it...
The 351w will also sit taller in the engine bay as it has a taller block, but that's not of any great consequence with the RCR - depending upon your transaxle choice. Audi will require it to sit taller yet.
The 351w will not make any more power than the 347 stroker, but the 351w will generally make a bit more torque lower in the RPM band..

EFI is expensive - but Webers are as well.. Single 4 BBL carbs enjoy far greater simplicity of both electrical and fuel systems.

A lot of answers in here - you just need to sort through them and use what you can..

 

[Graham]

Hi Graham,

If you already have the headers for your car and they're for the 289-302, you're not going to be able to use them for the 351w.
For my money - I will never build a 347 from a stock block as I've seen/heard of too many block failures when being trashed at the track. Even though your purposes are mostly road use, I would still be very leery of the block's strength.
Now if you based it on the new Ford Boss 302 block - go for it...
The 351w will also sit taller in the engine bay as it has a taller block, but that's not of any great consequence with the RCR - depending upon your transaxle choice. Audi will require it to sit taller yet.
The 351w will not make any more power than the 347 stroker, but the 351w will generally make a bit more torque lower in the RPM band..

EFI is expensive - but Webers are as well.. Single 4 BBL carbs enjoy far greater simplicity of both electrical and fuel systems.

A lot of answers in here - you just need to sort through them and use what you can..

I have no engine components at all at the moment so I am nearly starting out with a blank canvas. I do have the bundle of Snakes for a 302 and I also have an Audi 016 tranny. Can I get 400 HP out of a 302 and still get good torque, or would it have to be a screamer? I (like everyone else) am on a budget that will only stretch so far...

Thanks for your help Randy,

Graham.

 

[Mike Drew]

For my GT350 clone, I'm having a 331 stroker built using a Mexican-block 302 as a foundation (the Mexican blocks were heavier/better than the run-of-the-mill US counterparts). The 331 seems to offer the ideal compromise for stroking, as it doesn't go as far as the 347, which has proven to have longevity problems with track use.

I am hoping for about 440 hp from my 331...but then again, I've been hoping my 331 would be finished since about 2005! :veryangry:

Long, sad story there....

 

[Randy V]

I have no engine components at all at the moment so I am nearly starting out with a blank canvas. I do have the bundle of Snakes for a 302 and I also have an Audi 016 tranny. Can I get 400 HP out of a 302 and still get good torque, or would it have to be a screamer? I (like everyone else) am on a budget that will only stretch so far...

Thanks for your help Randy,

Graham.

Hi Graham,

I built a 331 Stroker for mine and it's got a very mild cam ground specifically for Webers. It dyno'ed at ~415 HP and has throttle response like you would not believe (although I've yet to have driven it except for the engine dyno).. The 331 Eagle Stroker kits are very affordable and I think would be a better way to go than to try and wring the neck of a 302 to hit 400 HP.

So - given that you have the exhaust and an 016 - I would think that the budget minded choice would be the 302/331..

BTW - Although 415 hp is more than enough to move a car like this quite briskly - I will be changing out valve springs and possibly the cam for a slightly warmer grind that will bring net 450 HP without drama..

 

[Brett James-McCall]

I have no engine components at all at the moment so I am nearly starting out with a blank canvas. I do have the bundle of Snakes for a 302 and I also have an Audi 016 tranny.

Graham,
If you are starting out blank, then try to get a block that is pre 1 August 1975, then there is no emissions test. You can get 400bhp out of the block, but you will be on the limits of the tranny; there are however some case upgrades you can do so it makes it stronger.

For me, as I am on a budget, been building for years and now just want to get the car on the road, have opted for less power and will look to upgrade once it is all registered etc.

For info the old Edelbrock power package used to do 367bhp and 340ft lbs. They don't seem to put this up on thier site anymore. See attached.

PS if you ever want to chat, PM me for my mobile number

Brett

 

[Graham]

Damn, sometimes I wish I lived in the US....

The cost of V8 muscle over here is HEAVY... and as for a 331, I'm struggling to find people that do that configuration over here, it seems to be the usual 347 / 351 options. I've googled the Eagle kit you mentioned and it seems reasonable at around $1,100. If I bought the kit from the US, then I only need to get a company over here to bore the block out to a 331.... or am I MASSIVELY oversimplifying?

Randy, you really should start a V8 export company

Cheers, and any more advice is always welcome.

Graham.

 

[Graham]

Graham,
If you are starting out blank, then try to get a block that is pre 1 August 1975, then there is no emissions test. You can get 400bhp out of the block, but you will be on the limits of the tranny; there are however some case upgrades you can do so it makes it stronger.

For me, as I am on a budget, been building for years and now just want to get the car on the road, have opted for less power and will look to upgrade once it is all registered etc.

For info the old Edelbrock power package used to do 367bhp and 340ft lbs. They don't seem to put this up on thier site anymore. See attached.

PS if you ever want to chat, PM me for my mobile number

Brett

Brett,

Thanks for the Info. As to the Tranny, then yes I agree, its pretty much up around the limit, to the point where you wouldn't want to be dropping the clutch too heavily with some revs too often. As to the case upgrades, that's interesting, and I may take you up on the offer of a chat soon. As I have the tranny, then now is probably as good a time as any to get the mods done. I'll add it to my list of things to do :laugh::laugh::laugh:

Cheers pal,

Graham.

 

[Brett James-McCall]

Palte info available here: http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/28243-audi-trans-axle-strengthen.html

 

[Jon Briggs]

Damn, sometimes I wish I lived in the US....

The cost of V8 muscle over here is HEAVY... and as for a 331, I'm struggling to find people that do that configuration over here, it seems to be the usual 347 / 351 options. I've googled the Eagle kit you mentioned and it seems reasonable at around $1,100. If I bought the kit from the US, then I only need to get a company over here to bore the block out to a 331.... or am I MASSIVELY oversimplifying?

Randy, you really should start a V8 export company

Cheers, and any more advice is always welcome.

Graham.

I would say that there are allot of issues with importing from the states. One is finding a company that will sell to you and ship to the UK. The Americans have allot of problems excepting foreign credit cards. They also tend to be very expensive on shipping to the UK, Summit wanted $500 to ship a Cam kit and heads. But the overriding problem is here in the UK.

Customs will charge you 5% of the cost of the items and shipping in duty, then they will slap VAT on to the total at 17.5%. They also use their own dollar exchange rate which is way below the commercial rate. The last I checked it was 1.45 to the pound, when the exchange rate was 1.65. So it worked out I was not saving very much and I would be very out of pocket if anything was wrong with the order.

Now if you were to take a holiday to the US, and carry a spare suitcase or take the items to the post office yourself, that would be an entirely different case. If you see what I mean.

 

[Simon]

graham, a 331 wil use standard/+30/+60 bores, it's the crank throw thats longer. i built a 331 stroker and just had to relieve the lower portion of the bores with a dremel
simon
ps 'twas a nice engine

 

[Brian Hamilton]

The best stroker engine from the 302 foundation is the 331. The reason is the 347 puts the wrist pin up in the piston rings and thus destroys the longevity of the engine. If you don't mind pulling the engine and rebuilding it every year or 2, then go ahead, the 347 makes tons of power if done correctly. Now, the 351-w will stroker to 427 cid, and we all know that's a magic number that's near and dear to any Ford lover. You do get into issues with going to the max on any stroker engine build, but like suggested earlier, the tall deck blocks will get rid of any of these problems. If you are looking for an inexpensive stroker build, the 331 is probably the best bang for the buck. Throw some AFR or Trick Flow heads on there and go to town. If you're going to build a 351 stroker, either find an older 69' and earlier block due to the high nickel content or get a new block from an aftermarket manufacturer who's strengthened them. The later blocks seem to not like being stroked much past a 408, well they do like it, just not for long. LOL You can also get a roller conversion that comes with a roller lifter "spider" that holds the lifters in place and you just tap the lifter valley for the bolts that hold it down. Last priced, it was under $100. That's a great investment I think for longevity and a little more performance from reduced friction.

Again, this is opinion, but also there's quite a bit of experience in there from engines I've seen run like champs and engines I've seen blow sky high in a most spectacular fashion at the old performance shop I worked at. Lots of fun. I am a biased 351-W fan though so I'd say go that route. Hehe.

 

[Terry Oxandale]

I've done both, and then did a 383 (351 stroker). I eventually stuck with the 383 for power and torque, it had the same cost as stroking a 302, the 351 block was stronger than a 302 block (OEM blocks), and the RL/Stroke ratio was pretty decent with the 6.25 rods on the stroker, and lastly, 400+ hp was childs play.
The down side was an additional 46 lbs and wider, taller assembly. Once you get used to the torque, you can't go back, but the Audi transaxle strength will be probably be the most important factor is what you decide to do.

 

[andy loveday]

Graham,
If you are starting out blank, then try to get a block that is pre 1 August 1975, then there is no emissions test. You can get 400bhp out of the block, but you will be on the limits of the tranny; there are however some case upgrades you can do so it makes it stronger.

For me, as I am on a budget, been building for years and now just want to get the car on the road, have opted for less power and will look to upgrade once it is all registered etc.

For info the old Edelbrock power package used to do 367bhp and 340ft lbs. They don't seem to put this up on thier site anymore. See attached.

PS if you ever want to chat, PM me for my mobile number

Brett

Brett , think you find the vis smoke test has now gone with the IVA test :thumbsdown:, deal done with europe they wanted no dated blocks, all had to be tested like new engines, your still good up too 1993 then its new test limits, Andy

 

[Mike Huddart]

Brett , think you find the vis smoke test has now gone with the IVA test :thumbsdown:, deal done with europe they wanted no dated blocks, all had to be tested like new engines, your still good up too 1993 then its new test limits, Andy

Andy,
I checked with VOSA after this subject came up in an earlier thread. I was told by VOSA last year that for the new IVA regs the visible smoke test was being dropped, then in the last week before IVA came in they abandoned the plan and it still applies. Thats for now, there will probably be changes to the format in the near future so it would be safer to plan ahead for sricter testing if anybody is contemplating a long build time
Mike

 

[andy loveday]

Andy,
I checked with VOSA after this subject came up in an earlier thread. I was told by VOSA last year that for the new IVA regs the visible smoke test was being dropped, then in the last week before IVA came in they abandoned the plan and it still applies. Thats for now, there will probably be changes to the format in the near future so it would be safer to plan ahead for sricter testing if anybody is contemplating a long build time
Mike

Thanks for the update mike, Andy :thumbsup:

 

[Woody]

Hi Graham
Lots of good info there for you to chew over. If with your budget you are looking to run a stock block I can confirm 400hp is about your limit. In the past I have run in a class here called pre 65's basically any thing 1965 and older. We ran a mustang with a 289 and it had to run a stock block. at 400hp it ran strong but then as we developed it we were making 450hp on the nose and the blocks started to break. even with a girdle they broke in the front main bearing area. We were allowed to run later model blocks but they too suffered the same demize. 400hp is cool any more and an after market block is a must.
I hope this helps
Woody

 

[Martin]

Andy,
I checked with VOSA after this subject came up in an earlier thread. I was told by VOSA last year that for the new IVA regs the visible smoke test was being dropped, then in the last week before IVA came in they abandoned the plan and it still applies. Thats for now, there will probably be changes to the format in the near future so it would be safer to plan ahead for sricter testing if anybody is contemplating a long build time
Mike

Mike I've heard a lot about the changes to the IVA recently from different sources. I'm looking to get mine through within the next 12 months. Do you think the test will change in that time ?

I'm running stack injection throttle bodies and motec on an eighties block so I'm hoping emmissions will be o.k. It's the Cats I want to avoid.
I opted for a 331 stroker engine for the reasons mentioned above. Rod ratio etc. The thing with a 331 is it MUST be balanced well, same for 347 i guess too with clutch and flywheel. It's critical. I'm getting just over 500Hp dynoed at the flywheel on mine but it did cost a bomb to get built.
Martin

 

[Graham]

Thanks to all of you for your help, and apologies for not getting back to some of you sooner. Our house was burgled yesterday :furious:

Some little bast*ards are out there with some of my stuff....

Luckinly, they did a smash and grab and just took some money and odds and sods, nothing sentimental or overly valuable... and not the GT40!!!

Cheers,


Graham

 

[Graham]

graham, a 331 wil use standard/+30/+60 bores, it's the crank throw thats longer. i built a 331 stroker and just had to relieve the lower portion of the bores with a dremel
simon
ps 'twas a nice engine

Hi Simon,

Thats Interesting (and shows my lack of knowledge on these things). So you are basically saying that a 331 is a 302, with no bore change at all. It is simply the distance of the throw, i.e the distance the piston travels in total that makes up the extra Cubic inches.

If I/ve got this wrong, then please feel free to take the mickey out of me. I'm a TOTAL newb with V8's...

Cheers,

Graham.